/*-
 * Copyright (c) 2010-2012 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This material is based upon work partially supported by The
 * NetBSD Foundation under a contract with Mindaugas Rasiukevicius.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * NPF logging extension.
 */

#ifdef _KERNEL
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: npf_ext_log.c,v 1.17 2020/05/30 14:16:56 rmind Exp $");

#include <sys/types.h>
#include <sys/module.h>

#include <sys/conf.h>
#include <sys/kmem.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/queue.h>

#include <net/if.h>
#include <net/if_types.h>
#include <net/bpf.h>
#endif

#include "npf_impl.h"
#include "if_npflog.h"

NPF_EXT_MODULE(npf_ext_log, "");

#define NPFEXT_LOG_VER          1

static void *           npf_ext_log_id;

typedef struct {
        unsigned int    if_idx;
} npf_ext_log_t;

static int
npf_log_ctor(npf_rproc_t *rp, const nvlist_t *params)
{
        npf_ext_log_t *meta;

        meta = kmem_zalloc(sizeof(npf_ext_log_t), KM_SLEEP);
        meta->if_idx = dnvlist_get_number(params, "log-interface", 0);
        npf_rproc_assign(rp, meta);
        return 0;
}

static void
npf_log_dtor(npf_rproc_t *rp, void *meta)
{
        kmem_free(meta, sizeof(npf_ext_log_t));
}

static bool
npf_log(npf_cache_t *npc, void *meta, const npf_match_info_t *mi, int *decision)
{
        struct mbuf *m = nbuf_head_mbuf(npc->npc_nbuf);
        const npf_ext_log_t *log = meta;
        struct psref psref;
        ifnet_t *ifp;
        struct npfloghdr hdr;

        memset(&hdr, 0, sizeof(hdr));
        /* Set the address family. */
        if (npf_iscached(npc, NPC_IP4)) {
                hdr.af = AF_INET;
        } else if (npf_iscached(npc, NPC_IP6)) {
                hdr.af = AF_INET6;
        } else {
                hdr.af = AF_UNSPEC;
        }

        hdr.length = NPFLOG_REAL_HDRLEN;
        hdr.action = *decision == NPF_DECISION_PASS ?
            0 /* pass */ : 1 /* block */;
        hdr.reason = 0; /* match */

        struct nbuf *nb = npc->npc_nbuf;
        npf_ifmap_copyname(npc->npc_ctx, nb ? nb->nb_ifid : 0,
            hdr.ifname, sizeof(hdr.ifname));

        hdr.rulenr = htonl((uint32_t)mi->mi_rid);
        hdr.subrulenr = htonl((uint32_t)(mi->mi_rid >> 32));
        strlcpy(hdr.ruleset, "rules", sizeof(hdr.ruleset));

        hdr.uid = UID_MAX;
        hdr.pid = (pid_t)-1;
        hdr.rule_uid = UID_MAX;
        hdr.rule_pid = (pid_t)-1;

        switch (mi->mi_di) {
        default:
        case PFIL_IN|PFIL_OUT:
                hdr.dir = 0;
                break;
        case PFIL_IN:
                hdr.dir = 1;
                break;
        case PFIL_OUT:
                hdr.dir = 2;
                break;
        }

        KERNEL_LOCK(1, NULL);

        /* Find a pseudo-interface to log. */
        ifp = if_get_byindex(log->if_idx, &psref);
        if (ifp == NULL) {
                /* No interface. */
                KERNEL_UNLOCK_ONE(NULL);
                return true;
        }

        if_statadd2(ifp, if_opackets, 1, if_obytes, m->m_pkthdr.len);
        if (ifp->if_bpf) {
                /* Pass through BPF. */
                bpf_mtap2(ifp->if_bpf, &hdr, NPFLOG_HDRLEN, m, BPF_D_OUT);
        }
        if_put(ifp, &psref);

        KERNEL_UNLOCK_ONE(NULL);

        return true;
}

__dso_public int
npf_ext_log_init(npf_t *npf)
{
        static const npf_ext_ops_t npf_log_ops = {
                .version        = NPFEXT_LOG_VER,
                .ctx            = NULL,
                .ctor           = npf_log_ctor,
                .dtor           = npf_log_dtor,
                .proc           = npf_log
        };
        npf_ext_log_id = npf_ext_register(npf, "log", &npf_log_ops);
        return npf_ext_log_id ? 0 : EEXIST;
}

__dso_public int
npf_ext_log_fini(npf_t *npf)
{
        return npf_ext_unregister(npf, npf_ext_log_id);
}

#ifdef _KERNEL
static int
npf_ext_log_modcmd(modcmd_t cmd, void *arg)
{
        npf_t *npf = npf_getkernctx();

        switch (cmd) {
        case MODULE_CMD_INIT:
                return npf_ext_log_init(npf);
        case MODULE_CMD_FINI:
                return npf_ext_log_fini(npf);
                break;
        case MODULE_CMD_AUTOUNLOAD:
                return npf_autounload_p() ? 0 : EBUSY;
        default:
                return ENOTTY;
        }
        return 0;
}
#endif